Active and Passive Mode-Locked Fiber Lasers for High-Speed High-Resolution Photonic Analog-to-Digital Conversion

Abstract

We present a complete set of mode-locked fiber lasers designed for photonic analog-to-digital conversion. Design, simulation, fabrication, and characterization of Er-doped fiber lasers are carried out through optimizing their performance to suit the requirements of high-speed and high-resolution photonicassisted analog-to-digital converters. The required properties are achieved by active mode-locking on the basis of amplitude modulation of the cavity losses through a Mach-Zehnder modulator, and passive mode-locking on the basis of fast semiconductor saturable absorbers and intracavity polarizing fibers. The use of an intracavity polarizing fiber in combination with a fast saturable absorber allows dynamic control of the operation regimes through polarization control. Besides these oscillators designed with ring cavity structure, a short linear cavity with fundamental repetition frequency at the order of 1 GHz is studied, and an effective continuous tunability of the repetition frequency is obtained by an electromechanical transducer. Pulsed repetition rates up to 20 GHz, pulsewidths down to 500 fs, and time jitters below 180 fs are obtained. Fiber lasers based on standard and commercially available telecom devices are demonstrated to be a low-cost, compact, and versatile optical source for photonic-assisted analog-to-digital conversion.

2 μm passively mode-locked thulium-doped fiber lasers with Ta2AlC-deposited tapered and side-polished fibers

“…In the latter, the oscillating longitudinal modes present in the laser cavity are phase locked when an optical component is introduced in the optical cavity. Pulse generation in fiber lasers could be obtained using two main techniques; namely active and passive 34 . Active techniques require the use of external modulators such as acousto-optic and electro-optic modulators 35 .…”

2 μm Passively Mode-Locked Thulium-doped Fiber Lasers with Ta2AlC-deposited Tapered, Side- polished and D-shaped Fibers

“…In the latter, the oscillating longitudinal modes present in the laser cavity are phase locked when an optical component is introduced in the optical cavity. Pulse generation in ber lasers could be obtained using two main techniques: active and passive techniques 34 . Active techniques require the use of external modulators such as acousto-optic and electro-optic modulators 35 .…”

Experimental investigation of the cavity modulation frequency detuning effect in an active harmonically mode-locked fiber laser

“…High repetition rate optical pulses have been used as a light source for a variety of applications, such as high-speed optical communication [1], biomedical imaging [2], and optical analog-to-digital conversion [3]. One commonly used technique for the generation of high repetition rate optical pulses is active harmonic mode locking, which is usually implemented by a modulating cavity loss at a harmonic frequency of the fundamental resonance frequency.…”